Optical communication systems often use wavelength-division multiplexing (WDM) or dense wavelength-division multiplexing (DWDM) to transmit information in an optical fiber. Such techniques often involve packing voluminous amounts of information into signals and transmitting the signals simultaneously over the same fiber. Each signal is uniquely propagated on a different center frequency in the fiber so it can be recognized when received at a receiving end of a transmission system.
Today, optical equipment manufacturers are challenged with making more efficient use of installed fiber to increase available bandwidth while reducing the cost of deployment. Passive optical components, such as optical monitoring equipment, are commonly used to meet this challenge. The optical monitoring equipment is used to monitor performance of each signal transmitted in a fiber, to ascertain impediments such as power transients and loss of signals.
Unfortunately, the resolution demands necessary to identify signal characteristics are usually beyond the capabilities of telecom-grade monitoring equipment positioned between the ingress and egress points in an optical path. As a result it is often necessary to identify signals and their respective attributes by inference, which may be further encumbered by noise sources, large channel power ranges, and center-frequency misalignment. Accordingly, it is difficult to efficiently and reliably identify signals transmitted in a fiber optic system using telecom-grade monitoring equipment today.